This is, as others have mentioned, also doing the rounds as Sorceror and the... This is more appropriate but still misleading. A more accurate title would be "The Buddhist Abbot Who Uses Buddhist Magic To Fight Demons". Admittedly this lacks a certain something as a catchy title, like not being catchy. No matter.
If you like Chinese fantasy movies you'll certainly like this one. If you aren't familiar with them you may find it a little strange as Chinese myth and folktales are very different from their European equivalents. Also, don't expect much in the way of martial arts either. What you're actually getting is a romantic fantasy. When one of two snake demon sisters (who can wear human form/half human, and all giant snake) surprises a nice altruistic young man into falling off a cliff into a lake, her white snake sister saves him from drowning by kissing him which causes them to fall in love. Meanwhile, Abbot Jet Li and his young assistant are hunting down nasty demons and consigning them to another dimension where there's nothing to do but meditate on their sins and seek salvation. Susu, the white snake, pursues our young hero and they get married. When Jet Li finds out all hell breaks loose as a demon is a demon and they aren't meant to fall in love with humans because it won't work.
This film manages to do several things and mostly quite well. It's a nice romantic story with teasing gentle humour (at least in the early stages). It's also a monster-fighting action movie. It's other things as well but to say what they are would spoil it. The acting is standard for this type of Chinese film. The special effects and cgi are mostly pretty good and the climax is spectacular. It's not too long either with the end credits starting at the 87 minute mark.
Perhaps not the best introduction to Chinese fantasy but fun for afficionados.